Fibers (keratinous fibers) such as wool possess a scaly surface structure. Owing to this structure, the fibers tend to tangle and mat together when they are washed, and they shrink. Conventionally, the following methods which make use of silicone treatment agents have been proposed to overcome this disadvantage.
Japanese patent Kokoku (Japanese Examined Published Patent) 48-33435 proposes a method employing a composition comprising an organic solvent solution of a straight chain polysiloxane with terminal hydroxyl groups and a viscosity of no less than 50 cSt, and a catalyst.
Japanese Patent Kokoku 48-38036 proposes a method employing a chlorinated solvent solution of a high molecular weight polysiloxane and a catalyst.
Japanese Patent Kokoku 53-28468 proposes a method employing a composition of a diorganopolysiloxane with amino groups and alkoxyl groups.
Japanese Patent Kokoku 58-4114 proposes a method employing a composition of an organopolysiloxane with mercapto groups and amino groups.
The effect of these anti-shrink agents was however invariably inadequate when the fibers were washed, and in particular, anti-shrink properties were not retained if they were washed repeatedly. Further, the feel of treated fiber products tended to be lost, and no anti-shrink softener which could withstand washing had therefore been perfected.
The inventors discovered an anti-shrink softener which was durable with regard to washing, and arrived at the present invention.